Compensation rings are used in making rotating machines like electric motors and similar items, where what is required most is a reduction of the noises caused by the rotating parts. The principal sources of noise in machines are due to the slackening of the balls in the ball races in bearings. This tolerance can be reduced by using these rings and applying pressure on the outer ring of the bearing so that more silent running is possible. By fitting compensation rings motor shafts can expand without compromising the rotating parts and their seats. In addition, they make it possible to make up for any centre errors that may be encountered in constructing an electric motor.